Separation by Intermediate Pressure and its Application to Acetylene Purification

Abstract

Theoretical studies were made on the separation by intermediate pressure in a multi-component system. Theseparation procedure by intermediate pressure is often applied in chemical industry. The aim is to strip impuregas or to take out the solvent dissolved gas in its pure state.
Originally, the dissolving equilibrium of gases into gas phase and liquid phase was in many cases measuredby Henry's law and its treatment should be easy, but calculations of separation by intermediate pressure wereusually performed by the trial and error method which especially caused great trouble and took a long time inthe case of multi-components.
As a result of this paper, analysis on this problem became feasible either algebraically when the system iscomposed of up to four components or graphically when composed of multi-components (more than four components).
Applying this procedure to the purification of acetylene in a reaction gas by partial oxidation of Methane, itwas confirmed that the purity of product acetylene was higher in case of two stage expansions compared withsingle expansion. Furthermore, investigation on optimum intermediate separating pressure in multi-componentsystem which contained gas of less methanol-solubility such as Hydrogen, Carbon monooxide, Methane, Nitrogenshowed that optimum pressure lay closer to final expansion pressure and in 1.5-2.0 atm in this example.